*{
    /*设定的宽度和高度分别减去边框和内边距才能得到内容的宽度和高度。*/
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
.nav{
    position: fixed;
    width:100%;
    height:103px;
    background-color:rgb(0, 255, 208);
    top:0;
    border-bottom: 2px solid red;
    z-index: 100;
}
.head{
    /*background-color:antiquewhite;*/
    height:104px;
    width: 1200px;
    margin: 0 auto;/*使居中*/
    position: relative;
}
.img-head{
    width: 180px;
    margin: 7px 0;
    height: 90px;
}
.head ul{
    list-style: none;
    position: absolute;
    left: 230px;
    height:20px;
    top:50%;/*，使居中。设置span时，margin为0*/
    margin-top: -10px;
    font-size: 20px;
    line-height: 20px;;/*行居中*/
    /*top的50%是以文字顶部为界限*/
}
.head ul li{
    float: left;
    border-right: 1.5px solid #6c6c6c;
}
.head ul li span{
    color: #6c6c6c;
    margin: 0 15px;
}
.head ul li a{
    text-decoration: none;
}
/*去除选中时，最左和最有的空白*/
.head ul li:first-child span{
    margin-left: 0;
    font-family: 600px;
}
/*去掉最后边的竖线*/
.head ul li:last-child{
    border-right: none;
}
.head ul li:last-child span{
    margin-right: 0;
}



/*轮播图*/
.banner{
    position:relative;
    top:103px;
    width:790px;
    height:540px;
    /*background-color: red;测试时使用的颜色 */                                                                                                                                                                                                               
    margin: 100px auto;     
    overflow: hidden;/*溢出时隐藏，使后面的图片先藏起来*/                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
}
.banner ul{
    width:3952px;      
    height: 540px;
    position: absolute;
   /* border: 1px solid rgb(196, 209, 81);*/

}
.banner ul li{
    list-style-type:none;
    width:790px;
    height: 540px;
    float: left;
}
.banner ul li img{
    height: 540px;
    width:790px;
}
/*轮播图的圆圈*/
a{
    text-decoration: none;
}
.num{
    width: 100%;
    height: 20px;
    background-color: #6c6c6c;
    position: absolute;
    left: 0;
    bottom: 10px;
    text-align: center;
}
.num span:hover{
    background-color: #ccc;
}
.num span{
    width: 15px;
    height:15px;
    border-radius: 50%;
    background-color: white;
    display:inline-block;
    margin: 0 8px;
}
.num span:hover{
    cursor: pointer;
}
/*向左向右的箭头    prev() 方法返回被选元素的前一个同级元素*/
a{
    text-decoration: none;
}
.banner .prev{
    display: block;
    width:40px;
    height:74px;
    background-color:rgb(0,0,0,0.2);
    color:rgb(255,255,255,0.4);
    left:0;
    top:50%;
    z-index: 100;
    position: absolute;
    margin-top: -37px;
    text-align: center;
   /*其实background-color加不加都可以*/
}
.banner .next{
    display: block;
    width:40px;
    height:74px;
    background-color:rgb(0,0,0,0.2);
    right:0;
    top:50%;
    z-index: 100;
    position: absolute;
    margin-top: -37px;
    text-align: center;
    color:rgb(255,255,255,0.4);
    transition:background-color .3s ;
}
.prev i,
.next i{
    font-size: 30px;
    line-height: 74px;

}
.prev:hover,
.next:hover{
    background-color:rgb(0, 0,0,0.5);
    color:#fff;
}
/*圆圈变椭圆*/
.num span.on{
    width:30px;
    height:15px;
}